Actually, it's not bad. I've traveled Europe under Bush, Obama, and this year. With Bush it was awful. I traveled with a Canadian flag patch on my bag and know how to say "No! No, Canadian" in 6 languages. After 2008 it was amazing. Everyone loved you and the flag patch was a funny ice breaker. Now, they just seen to feel sympathy for you. There's none of the blaming individual Americans for the president at all. I was prepared for it, but it just wasn't there this time.
It depends. When Americans travel with mistrust, inflated ego and arrogance - why would they be welcomed? You need to be somewhat humble to be welcomed, no matter where you're from. I think much of the world is worn out at this point, unless you're an obese guy with a stars and stripes t-shirt, no-one will be hostile towards you.
